1. Field of the Invention:
This invention relates to partial esters of saturated, linear C.sub.22 -C.sub.34 -monocarboxylic acids with polyols, to a process for their production and to their use as release agents for plastics, particularly those based on PVC or PVC copolymers. The invention also relates to molding compositions, especially compositions based on PVC or PVC copolymers, containing these partial esters.
For many years, full esters of saturated, linear C.sub.22 -C.sub.34 monocarboxylic acids with polyols have played an important part in the processing of PVC and PVC copolymers, especially as release agents in calendering processes. They combine a good release effect with a relatively high PVC-compatibility, which is particularly pronounced in the case of high-impact or semi-rigid formulations. Conventional applications include the use of these full esters in the production of modified, glass-clear packaging films based on suspension or mass PVC and also the production of heat treated emulsion PVC films, for example for adhesive tape manufacture. In the latter case, the good compatibility of the full ester with PVC is particularly important because of the limit of the usable quantities can easily lie at 5 pbw. By contrast, a disadvantage of these known esters is the extremely low transparency limit in unmodified rigid PVC. Typically employed in these processes are full esters of ethylene glycol, 1,3-butanediol or glycerol with montanic acids of the type obtainable by conventional oxidative bleaching of montan waxes, or mixtures of predominantly saturated, linear C.sub.22 -C.sub.34 -carboxylic acids containing an even number of carbon atoms. The term "montanic acids" as used herein refers to the acids derived from montan waxes by any known process.
2. Discussion of Related Art:
Partial esters of C.sub.8 -C.sub.22 -fatty acids esterified with mono-and disaccharides, wherein each mono-or disaccharide unit contains at least four C.sub.8 -C.sub.22 -fatty acid residues are known; for example, such partial esters, used as low-calorie edible fats, are described in U.S. Pat. No. 3,600,186.